Protein kinases include a large set of structurally related phosphoryl transferases which catalyze the transfer of the terminal phosphate from ATP to the hydroxyl group of tyrosine, serine and/or threonine residues of proteins. Protein kinases are categorized into families by the substrates they phosphorylate, for example, protein tyrosine kinases (PTK) and protein serine/threonine kinases.
Phosphorylation via protein kinase(s) results in a functional change of the target protein (substrate) by changing enzyme activity, cellular location or association with other proteins. Protein kinases play vital role, not only in controlling cell growth and differentiation, but also in regulating a wide variety of cellular signal transduction pathways in which protein kinases effectively regulate production of growth factors and various cytokines such as tumor necrosis factor (TNF)-α. Examples of protein-tyrosine kinases include SYK, PYK2, FAK, ALK, AXL, CSF1R, FLT3, JAK2 (JH1domain-catalytic), JAK3 (JH1domain-catalytic), KIT, KIT (D816V), KIT (V559D, T670I), PDGFRB, RET, TYK2 and ZAP70. Examples of protein-serine/threonine kinases include PIM1, AURKA, AURKB, BMPR2, JNK1, JNK2, JNK3, LKB1, LRRK2, LRRK2(G2019S), MLK1, PAK4, PLK4, RSK2 (Kin.Dom.1-N-terminal), SNARK, SRPK3 and TAK1.
Misregulation of these protein kinases has been implicated in numerous diseases and disorders such as central nervous system disorders (e.g., Alzheimer's disease), inflammatory and autoimmune disorders (e.g., asthma, rheumatoid arthritis, Crohn's disease, and inflammatory bowel syndrome, and psoriasis), bone diseases (e.g., osteoporosis), metabolic disorders (e.g., diabetes), blood vessel proliferative disorders, ocular diseases, cardiovascular disease, cancer, restenosis, pain sensation, transplant rejection and infectious diseases. Although biological and clinical importance of protein kinases has been recognized in the field, a continuing need exists for compounds which inhibit protein kinases to provide an effective and safe clinical therapy for the diseases associated with or mediated by protein kinases. A need also exists for methods of administering such compounds, pharmaceutical formulations and medicaments to patients or subjects in need thereof.